Calcium magneto-optical trap loaded from a decelerated atomic beam

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOWe describe a new system for laser cooling and trapping of neutral Calcium atoms employing the ¹S0 -¹ P1 resonant transition at 423 nm. An on-axis magneto-optical trap (MOT) is loaded from a Zeeman decelerated atomic beam. When a single laser is used, in order to avoid perturbation of the trap by the deceleration laser beam, this one has been tightly focused near the MOT center, with a waist size much smaller than the atomic cloud. In order to test the efficiency of this novel technique, we have then employed a second, independent decelerating laser, with a profile mode matched to the atomic beam. For an oven temperature of 580±C this system can load 1.2 (2) x 10(7) atoms in 16 (1) ms. By the spatial extension of the atomic cloud the one dimension rms velocity was estimated to be 136 (12) cm/s, corresponding to a temperature of 9 (2) mK. The variation of the number of trapped atoms as a function of laser detuning and intensity, trap magnetic field gradient and oven temperature is analyzed. Spatial structures of the trapped atoms, like stable rings created by vortex forces, have been observed. This is the first time that these structures, already observed in alkali-metal elements, are reported in MOTs of alkaline-earth elements.We describe a new system for laser cooling and trapping of neutral Calcium atoms employing the ¹S0 -¹ P1 resonant transition at 423 nm. An on-axis magneto-optical trap (MOT) is loaded from a Zeeman decelerated atomic beam. When a single laser is used, in order to avoid perturbation of the trap by the deceleration laser beam, this one has been tightly focused near the MOT center, with a waist size much smaller than the atomic cloud. In order to test the efficiency of this novel technique, we have then employed a second, independent decelerating laser, with a profile mode matched to the atomic beam. For an oven temperature of 580±C this system can load 1.2 (2) x 10(7) atoms in 16 (1) ms. By the spatial extension of the atomic cloud the one dimension rms velocity was estimated to be 136 (12) cm/s, corresponding to a temperature of 9 (2) mK. The variation of the number of trapped atoms as a function of laser detuning and intensity, trap magnetic field gradient and oven temperature is analyzed. Spatial structures of the trapped atoms, like stable rings created by vortex forces, have been observed. This is the first time that these structures, already observed in alkali-metal elements, are reported in MOTs of alkaline-earth elements.We describe a new system for laser cooling and trapping of neutral Calcium atoms employing the ¹S0 -¹ P1 resonant transition at 423 nm. An on-axis magneto-optical trap (MOT) is loaded from a Zeeman decelerated atomic beam. When a single laser is used, in order to avoid perturbation of the trap by the deceleration laser beam, this one has been tightly focused near the MOT center, with a waist size much smaller than the atomic cloud. In order to test the efficiency of this novel technique, we have then employed a second, independent decelerating laser, with a profile mode matched to the atomic beam. For an oven temperature of 580±C this system can load 1.2 (2) x 10(7) atoms in 16 (1) ms. By the spatial extension of the atomic cloud the one dimension rms velocity was estimated to be 136 (12) cm/s, corresponding to a temperature of 9 (2) mK. The variation of the number of trapped atoms as a function of laser detuning and intensity, trap magnetic field gradient and oven temperature is analyzed. Spatial structures of the trapped atoms, like stable rings created by vortex forces, have been observed. This is the first time that these structures, already observed in alkali-metal elements, are reported in MOTs of alkaline-earth elements.332355362FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOSem informaçãoSem informaçãoSem informaçãoWe would like to acknowledge the glass shop of the UNICAMP Physics Institute for the very well done work in the construction of the atomic beam and MOT glass chamber. We also would like to thank the machine shop and J.B.Rodrigues for the mechanical parts. This work was supported by FAPESP, CAPES and CNPq and FAEPUNICAMP, Brazilian government agencies. Support for RLCF was through CAPES graduate research scholarship and for DAM and DRO through FAPESP graduate and undergraduate scholarships respectively

Conserved presence of G-quadruplex forming sequences in the Long Terminal Repeat Promoter of Lentiviruses

G-quadruplexes (G4s) are secondary structures of nucleic acids that epigenetically regulate cellular processes. In the human immunodeficiency lentivirus 1 (HIV-1), dynamic G4s are located in the unique viral LTR promoter. Folding of HIV-1 LTR G4s inhibits viral transcription; stabilization by G4 ligands intensifies this effect. Cellular proteins modulate viral transcription by inducing/unfolding LTR G4s. We here expanded our investigation on the presence of LTR G4s to all lentiviruses. G4s in the 5'-LTR U3 region were completely conserved in primate lentiviruses. A G4 was also present in a cattle-infecting lentivirus. All other non-primate lentiviruses displayed hints of less stable G4s. In primate lentiviruses, the possibility to fold into G4s was highly conserved among strains. LTR G4 sequences were very similar among phylogenetically related primate viruses, while they increasingly differed in viruses that diverged early from a common ancestor. A strong correlation between primate lentivirus LTR G4s and Sp1/NF\u3baB binding sites was found. All LTR G4s folded: their complexity was assessed by polymerase stop assay. Our data support a role of the lentiviruses 5'-LTR G4 region as control centre of viral transcription, where folding/unfolding of G4s and multiple recruitment of factors based on both sequence and structure may take place

THE SIGNAL TO NOISE RATIO OF GASEOUS PHOTOACOUSTIC SYSTEMS

Measurement of small absorption coefficients of weakly absorbing or trace gases in the atmosphere has been one of the most important applications of laser photoacoustic devices. Normally, the major factor limiting the sensitivity of these systems is the spurious signal produced by the heating of the cell windows, due to the partial absorption of the laser pump radiation. We present a simple photoacoustic configuration that eliminates the spurious window and external background signals and enhances the main (real) signal of IR gaseous photoacoustic systems, optimizing the signal-to-noise ratio.33654955

Measurement And Assignment Of New Fir Laser Lines In12ch3oh And13ch3oh

We have found twelve new FIR laser lines in12CH3OH and thirty three in13CH3OH. Both molecules were pumped by a regular cw CO2 laser. We have also assigned 2013CH3OH laser lines to specific rotational energy levels in the excited C-O stretchhindered rotation combined states © 1987 Springer-Verlag.441676

Infrared optoacoustic spectroscopy of (CD3OD)-C-13 around the 10R and 10P CO2 laser lines

In this work we present the results of an investigation about Doppler limited infrared absorbing transitions of the C-O stretching vibrational mode of (CD3OD)-C-13 by means of optoacoustic detection. This technique is an alternative, more sensitive and of higher resolution than the Fourier transform spectroscopy which is applied to this methanol isotopomer, due to the contamination problem associated with the fast exchange of OD by OH in the molecule. Using a waveguide CO2 laser of 290 MHz tunability on each line we were able to observe 69 absorptions, most of then of large offset. The data will be useful in theoretical analysis of this sample, as well as a guide in the search for new FIR laser lines.17111821183

NEW OPTICALLY PUMPED FIR LASER LINES IN CD3OH

781241125

Hyperfine Structure Of The R(115) 20-1 Line Of127i2 At 570 Nm

The hyperfine spectrum of the iodine R(115)20-1 line, at 570 nm, was obtained by conventional saturated absorption spectroscopy. The differences of nuclear electric-quadrupole (Δe Qq) and spin-rotation (ΔC) constants between the B and X states were determined by a least-square fit to the experimental data. This line may provide a good frequency reference in coincidence with the1S0-1P1 resonant transition of magnesium, at 285 nm, when this one is investigated with frequency doubled lasers. © 1994 Società Italiana di Fisica.16215516

Infrared Optoacoustic Spectroscopy Of 13cd3od Around 9p Co2 Laser Lines

In this work we present the results of an investigation about Doppler limited infrared absorbing transitions of the in-plane methyl-rocking and the asymmetric methyl deformation modes of 13CD3OD by means of optoacoustic detection. This is an alternative and attractive technique to be applied to this methanol isotopromer, in comparison to Fourier transform spectroscopy. In fact the contamination problem associated with the fast exchange of OD by OH in the molecule limits the use of the Fourier transform technique. Using a waveguide CO2 laser of 290 MHz tunability on each line we were able to observe 20 IR absorptions, most of them of large offset. The data will be useful in theoretical analysis of this molecule, as well as in the generation of FIR laser radiation in optically pumped molecular laser.214621632Borden, A., Baker, F.E., (1939) J.Chem Phys., 6, p. 553Koehler, J.S., Dennison, D.M., (1940) Phys. Rev., 57, p. 1006Pereira, D., Moraes, J.C.S., Telles, E.M., Scalabrin, A., Strumia, F., Moretti, A., Carelli, G., Massa, C.A., (1994) Int. J. of Infrared and Millimeter Waves, 15 (1), p. 1Moruzzi, G., Moraes, J.C.S., Strumia, F., (1992) Int. J. of Infrared and Millimeter Waves, 13 (9), p. 1269Henkel, C., Jacq, T., Nuersberger, R., Menten, K.M., Steppe, H., (1987) Astron. Astrophys., 188 (1), pp. L1Sutton, E.C., Herbst, E., (1988) Astrophys. J., 333 (1), p. 359Moruzzi, G., Strumia, F., Carnesecchi, P., Mukhopadyay, I., Lees, R.M., Johns, J.W.C., (1989) Infrared Phys., 29 (2), p. 583Moruzzi, G., Riminucchi, P., Strumia, F., Carli, B., Carlotti, M., Lees, R.M., Mukhopadyay, I., Winnewisser, M., (1990) J.Mol. Spectrosc., 144 (1), p. 139Moraes, J.C.S., Scalabrin, A., Pereira, D., Dilonardo, G., Fusina, L., (1991) Infrared Phys., 31 (4), p. 365Moraes, J.C.S., Scalabrin, A., Pereira, D., Carelli, G., Ioli, N., Moretti, Strumia, F., (1992) Appl. Phys. B, 54 (1), p. 24Mukhopadyay, I., Lees, R.M., Llewis-Bevan, W., Johns, J.W., (1995) J. Chem. Phys., 102 (16), p. 6444Moraes, J.C.S., Pereira, D., Scalabrin, A., Moruzzi, G., Strumia, F., Winnewisser, B.P., Winnewisser, M., Gupta, P.K., (1995) J. Mol. Spectrosc., 174 (1), p. 177Moraes, J.C.S., Carelli, G., Moretti, A., Moruzzi, G., Strumia, F., (1996) J.Mol. Spectrosc. J. Mol. Spectrosc., 177 (2), p. 302Carelli, G., Ioli, N., Moretti, A., Moruzzi, G., Strumia, F., Zhao, S., Lees, R.M., Goulding, R.R., (1995) Infrared Phys.Tech., 35 (6), p. 743Carelli, G., Moretti, A., Strumia, F., Zhao, S., Lees, R.M., (1996) J. Mol. Spectrosc., 177 (1), p. 79Cruz, F.C., Scalabrin, A., Pereira, D., Vazquez, P.A.M., Hase, Y., Strumia, F., (1992) J. Mol. Spectrosc., 156 (1), p. 22Viscovini, R.C., Scalabrin, A., Pereira, D., (1996) Int. J. of Infrared and Millimeter Waves, 17 (11), p. 1821Carelli, G., Ioli, N., Messina, A., Moretti, A., Strumia, F., Telles, E.M., Moraes, J.C.S., Pereira, D., (1991) Infrared Phys., 31 (4), p. 323Telles, E.M., Moraes, J.C.S., Scalabrin, A., Pereira, D., Carelli, G., Ioli, N., Moretti, A., Strumia, F., (1994) IEEE J. Quantum Electron, QE30 (12), p. 2946Moraes, J.C.S., Telles, E.M., Cruz, F.C., Scalabrin, A., Pereira, D., Carelli, G., Ioli, N., Strumia, F., (1992) Int. J. Infrared and Millimeter Waves, 13 (11), p. 1801Viscovini, R.C., Scalabrin, A., Pereira, D., (1997) IEEE J. Quantum Electron, QE33 (6), p. 916Viscovini, R.C., Telles, E.M., Scalabrin, A., Pereira, D., (1997) Appl. Phys. B, 65 (1), p. 33Viscovini, R.C., Telles, E.M., Scalabrin, A., Pereira, D., (1999) IEEE J. Quantum Electron, QE35 (11), p. 1613Viscovini, R.C., Cruz, F.C., Moraes, J.C.S., Scalabrin, A., Pereira, D., (1999) Int. J. Infrared and Millimeter Waves, 20 (2), p. 193Telles, E.M., Moraes, J.C.S., Scalabrin, A., Pereira, D., Moretti, A., Strumia, F., (1991) Appl. Phys. B, 52 (1), p. 36Pereira, D., Scalabrin, A., (1992) Infrared Phys., 33 (6), p. 549Carelli, G., Ioli, N., Moretti, A., Pereira, D., Strumia, F., (1987) Appl. Phys. B, 44 (2), p. 11

New Optically Pumped Fir Laser Lines In Cd//3oh.

Laser action in 69 new FIR laser lines in CD//3OH optically pumped by a regular cw CO//2 laser. We have performed measurements of laser wavelength, optimum pressure of the gas, relative polarization and intensity on all lines, including some previously known.781241125

HYPERFINE-STRUCTURE OF THE R(115) 20-1 LINE OF I-127(2) AT 570 NM

The hyperfine spectrum of the iodine R(115)20-1 line, at 570 nm, was obtained by conventional saturated absorption spectroscopy. The differences of nuclear electric-quadrupole (DELTAe Qq) and spin-rotation (DELTAC) constants between the B and X states were determined by a least-square fit to the experimental data. This line may provide a good frequency reference in coincidence with the S-1(0)-P-1(1) resonant transition of magnesium, at 285 nm, when this one is investigated with frequency doubled lasers.16215516